It's the summer's most-anticipated movie, though no one seems to know exactly what it's about. For the most part, critics say it lives up to the hype, even if it's low on actual emotion.

Like writer/director Christoper Nolan's previous film Memento, Inception has a puzzle-like structure, and may require more than one viewing. Dom Cobb (Leonardo DiCaprio) and his partner Arthur (Joseph Gordon-Levitt) are experts at entering people's dreams and extracting secrets. He's approached by a Salto (Ken Watanabe), a Japanese businessman, and asked to plant information in the mind of the heir to a rival business (Cillian Murphy). (For some reason this reverse process is considered impossible.)

Dom enlists the help of an architect (Ellen Page), a "forger" who can impersonate anyone (Tom Hardy), and an anesthesiologist (Dileep Rao). They embark on a "three-level chess game involving a dream within a dream within a dream," which is sabotaged by Dom's wife, Mal (Marion Cotillard), who's dead, or imaginary or something. It's unclear, as the entire film is "really one giant hallucination."

Critics say the film is "wholly original," "yet structured with action movie basics so it feels like it makes more sense than (quite possibly) it does." While the actors are good, they're hampered by clunky dialogue. Dom and Mal's romance is "clunky" and Cotillard is underused — as in she literally gets locked away in a basement at one point. The film manages to hold your attention for two and a half hours (New York Magazine has helpfully provided a guide to when it's safe to use the bathroom), but as it "grows more complicated, it doesn't gather substance."

One of the best things about Nolan as a director is that he's not self-conscious. His movies unfold and fold in on themselves without the strain of labor or flash. But that lack of self-consciousness is also Nolan's downside. While "Inception'' grows more complicated, it doesn't gather substance. You feel the movie gliding, floating forward or down, but the depths feel only directional, never psychological. The many layers turn out to be an arrangement of surfaces. We're not inside a mind so much as an enormous boutique. Of course, these are other people's dreams, and they present to Cobb the same physical challenge they do to Nolan. How do you pull this off? Namely, by hoping your audience is too dazzled to ask.

The plan they come up with is a three-level chess game involving a dream within a dream within a dream, and by the rules the movie establishes, the whole scheme makes a kind of ingenious sense. The problem is that the emotional stakes are consistently too low for the viewer to engage with the story. It's never clear why we should care about the relationship between Murphy and his dying father, played by Pete Postlethwaite-their characters enter the story too late, and are too hastily sketched, to amount to anything more than types. Even more problematic is the love story between Dom and the specter of his late wife, Mal (Marion Cotillard). Until he can let Mal's memory go, we're told, Dom is perpetually in danger of becoming lost in the dream world. (Mal's name, by the way, means "evil" in French. Trowel!) The idea of being weighed down by the ghost of an old love is rich with narrative possibilities, but Dom and Mal's passion never stops feeling like a clumsy narrative contrivance, especially after Ariadne starts intervening as an amateur psychotherapist. In essence, all of Page's dialogue in these scenes amounts to variants on "Dom? Denial ain't just a river in Egypt."

The story can either be told in a few sentences, or not told at all. Here is a movie immune to spoilers: If you knew how it ended, that would tell you nothing unless you knew how it got there. And telling you how it got there would produce bafflement. The movie is all about process, about fighting our way through enveloping sheets of reality and dream, reality within dreams, dreams without reality. It's a breathtaking juggling act, and Nolan may have considered his "Memento" (2000) a warm-up; he apparently started this screenplay while filming that one. It was the story of a man with short-term memory loss, and the story was told backwards.

The movies often seem to come from the recycling bin these days: Sequels, remakes, franchises. "Inception" does a difficult thing. It is wholly original, cut from new cloth, and yet structured with action movie basics so it feels like it makes more sense than (quite possibly) it does. I thought there was a hole in "Memento:" How does a man with short-term memory loss remember he has short-term memory loss? Maybe there's a hole in "Inception" too, but I can't find it. Christopher Nolan reinvented "Batman." This time he isn't reinventing anything. Yet few directors will attempt to recycle "Inception." I think when Nolan left the labyrinth, he threw away the map.

But seeing Inception - or seeing it twice, which we suggest - does not answer all the riddles. This is a film more to admire than to cherish, one that aims to fascinate rather than to satisfy familiar impulses. It's a beautiful object, like a perpetually spinning top, not a living organism.

Though the plot is really one giant hallucination, it's an experience that doesn't blow your mind so much as challenge it. Viewers will have to work to keep up with all the shifting perspectives and layers of deceit. Inception is like the coolest, toughest final exam - or like the dream of one, in which you're suddenly in class and you realize you didn't prepare for the big test. This is a movie that you'll wish you had crammed for.

The selection of Oscar-winning French actress Marion Cotillard as Mal typifies the care Nolan has taken to cast these thriller roles for emotional connection, a move which pays off in the scenes she shares with DiCaprio. In addition to the impeccably professional Batman veterans Caine and Murphy, the film is also on the money with the smaller roles, including Pete Postlethwaite as Fischer's ailing tycoon father and Tom Berenger as one of his key associates.

It trades in crafty puzzles rather than profound mysteries, and gestures in the direction of mighty philosophical questions that Mr. Nolan is finally too tactful, too timid or perhaps just too busy to engage. So "Inception" is not necessarily the kind of experience you would take to your next shrink appointment. It is more like a diverting reverie than a primal nightmare, something to be mused over rather than analyzed, something you may forget as soon as it's over. Which is to say that the time - nearly two and a half hours - passes quickly and for the most part pleasantly, and that you see some things that are pretty amazing, and amazingly pretty: cities that fold in on themselves like pulsing, three-dimensional maps; chases and fights that defy the laws that usually govern space, time and motion; Marion Cotillard's face.

But though there is a lot to see in "Inception," there is nothing that counts as genuine vision. Mr. Nolan's idea of the mind is too literal, too logical, too rule-bound to allow the full measure of madness - the risk of real confusion, of delirium, of ineffable ambiguity - that this subject requires. The unconscious, as Freud (and Hitchcock, and a lot of other great filmmakers) knew, is a supremely unruly place, a maze of inadmissible desires, scrambled secrets, jokes and fears. If Mr. Nolan can't quite reach this place, that may be because his access is blocked by the very medium he deploys with such skill.

Managing all these nested levels of narrative is a marvelously nerdy accomplishment, no doubt — but this is the most tight-assed vision of the innermost human psyche I've ever seen. While Nolan's images are visually impressive and powered by state-of-the-art digital effects and accomplished stunt work, they're always ordered and organized with anal precision. They don't look or feel anything like dreams. (Or, at least, not like my dreams.) They look instead like mediocre action films from the '90s, or in the case of the supremely boring ski-patrol vs. Arctic fortress shootout found on Level Three, like the Alistair MacLean adaptation "Ice Station Zebra" from 1968. (With Rock Hudson! And Ernest Borgnine!) "Inception" may have been directed by Christopher Nolan, but Nolan's dreams are apparently directed by Michael Bay.

Sometimes Nolan's technical expertise produces its own kind of beauty, as in a startling zero-gravity scene in the hotel corridors when the laws of physics apparently rebel on Level Two. But for the most part "Inception" is a handsome, clever and grindingly self-serious boy-movie, shorn of imagination, libido, spirituality or emotional depth. Nolan establishes a fascinating world, loaded with trapdoors, symbols and hidden secrets, and then squanders the opportunity on an overpriced "Twilight Zone" episode. He casts Cotillard, one of the foxiest actresses alive, as a smoldering temptress who embodies all the female, erotic energy absent from this universe, and then literally locks her in the basement. Mal yearns to escape and get her claws into these constipated, narcoleptic boys (and maybe into Page's prim androgyne as well), and this movie would be a hell of a lot better if she did. But she's a girl — no, she's a woman — and even in dreams it's too dangerous to let those run around loose.

Like Nolan's 2001 indie breakthrough, "Memento," the film toys with themes such as the blurry line between perception and reality, the insidious nature of ideas, and the human capacity for self-delusion; significantly, it also focuses on an antihero captive to the memory of his dead wife. Because the picture privileges the mind over the heart, Cobb's unresolved guilt, intended as the story's tragic center, doesn't resonate as powerfully as it should, though the actors certainly give it their all: Cotillard is a presence both sultry and menacing, and DiCaprio anchors the film confidently, if less forcefully than he did the recent "Shutter Island" (in which he also played a widower at the mercy of dark visions).

Supporting roles are thinly written but memorably inhabited: Gordon-Levitt cuts a dashing figure; Hardy tears into his smartass supporting role with lip-smacking gusto; Watanabe brings elegance and gravity to his corporate raider; and Murphy plays the unsuspecting dreamer with poignant reserve. Page's repartee with DiCaprio could have been sharper in places, but the appealingly plucky actress makes Ariadne an ideal stand-in for the viewer.

Nolan sets up a uniquely difficult challenge for himself: In order for Inception to work, it has to reconcile the rational and predictable (represented by Page and her maze-like constructs) with dangerously fluid, irrational impulses (represented by DiCaprio and his fevered psyche). The Nolan of The Prestige and Memento is more naturally suited to the former than the latter; the vast cryptogram of Inception has a core of real emotion, but it isn't always matched by an abundance of visual imagination. Nonetheless, the film is an imposing, prismatic achievement, and strongly resistant to an insta-reaction; when it's over, Nolan still seems a few steps ahead of us.

While some dreamscape planning is almost as compelling as the wild reveries, the story bogs down occasionally in exposition and an overlong climactic scene. Page, ordinarily a subtle actress, wears the same expression throughout the film.
DiCaprio is terrific as the guilt-ridden Dom. Here and in Shutter Island, he plays haunted roles, each taking place primarily in his head.

Nolan has fashioned a story rich in off-kilter grandeur. But perhaps because we are so engaged in figuring out its plot, Inception doesn't fully connect emotionally. The film is easier to admire than to fully grasp or be moved by it. Still, it's worth surrendering to the dream.

The reality that jostles the reverie is that, as brainiacally engaging as the movie is, Inception's emotions beat with a much fainter pulse. Nolan outfits Dom with an old-fashioned love of wife and children, and waking-life emotions of grief and guilt. But between DiCaprio's characteristic (and, don't get me wrong, often interesting) affect of broody complication, and the generic nature of Dom's longings, the heart is far less engaged than the head for most of the show. I like the movie's ambition so much that I wish that imbalance didn't matter - that the daredevil rush to the (infernally open-ended) conclusion was its own satisfying reward. I'm left to hope, and wonder whether repeated viewing will shift my perspective. You know, as in a dream.

Rather than trying to game out "Inception" on first viewing, it's best to let it wash over you, and save the head-scratching and inevitable Talmudic interpretations for later. Chances are, there will be a later: "Inception" is the kind of film that will no doubt drive scores of viewers to theaters for a second go. But the key to success in a movie as purposefully complex as this one is that you see it again not because you have to, but because you want to. "Inception" is that rare film that can be enjoyed on superficial and progressively deeper levels, a feat that uncannily mimics the mind-bending journey its protagonist takes.

It may be that Mr. Nolan is purposely making his story obscure so as not to distract from his phenomenal image-making. If so, it's a waste of costly man hours. Mr. DiCaprio, it should be said, is a wonderful actor as well as an engaging screen presence, but his choices of late seem as suspect as "Inception." (The mysterious wife, the ephemeral kids, the fractured realities here all recall the recent "Shutter Island.") He's also as hampered as everyone else in the cast, needless to say, by the script. Each question asked by Cobb's dream team-Ariadne (Ellen Page), Eames (Tom Hardy), Arthur (Joseph Gordon-Levitt)-is answered a la the official "Inception" owner's manual: quickly, predictably, and as if it were all being made up on the fly. There is indeed an answer for everything: The sedative that doesn't allow a dreamer to return from the dream? I've adjusted it, says the team pharmacologist (Dileep Rao). What happens if someone is killed in dream but is sedated at the same time? Uh, he goes to Limbo, or "unconstructed dream space." They don't wink at each, quite, although when Ariadne asks, late in the game, "Whose subconscious are we going into, exactly?" it may be the biggest laugh line of the summer movie season.

Inception is full of brontosaurean effects, like the city that folds over on top of itself, but the tone is so solemn I felt out of line even cracking a smile. It lacks the nimbleness of Spielberg's Minority Report or the Jungian-carnival bravado of Joseph Ruben's Dreamscape or the eerily clean lines and stylized black-suited baddies of The Matrix-or, for that matter, the off-kilter intensity of Nolan's own Insomnia. The attackers in Inception are anonymous, the tone flat and impersonal. Nolan is too literal-minded, too caught up in ticktock logistics, to make a great, untethered dream movie.

For the record, I wanted to surrender to this dream; I didn't want to be out in the cold, alone. But I truly have no idea what so many people are raving about. It's as if someone went into their heads while they were sleeping and planted the idea that Inception is a visionary masterpiece and-hold on … Whoa! I think I get it. The movie is a metaphor for the power of delusional hype-a metaphor for itself.